Influence of Composition on Performance in Metallic Iron-Nickel-Cobalt Ternary Anodes for Alkaline Water Electrolysis

Metallic electrodes based on iron, nickel, and/or cobalt have re-emerged as promising cost-effective anodes for the alkaline oxygen evolution reaction (OER) due to their simplicity and their in situ formation of a highly active oxy-hydroxide surface catalyst layer, which exhibits state-of-the-art overpotentials for the OER. However, the effect of alloy composition has not been systematically studied. Herein, using metallic anodes with defined Fe-Ni-Co atomic ratios prepared via arc melting, we report the relationship between the initial alloy composition, the OER performance, and the emergent active catalyst composition. After 50 h operation at 0.5 A cm(-2) the most active initial alloys (having a moderate amount of cobalt